The Dana-Farber Cancer Institute, a teaching affiliate of the Harvard Medical School and an NCI-designated Comprehensive Cancer Center, has dedicated substantial support for resources which facilitate its research and training programs in its effort to develop and maintain a high-quality academic research environment. The Michael A. Redstone Laboratories for Animal Research represent one such major resource and are expected to serve as the Institute's primary animal research resource for at least the next decade. Consequently, the Institute is committed to improve and maintain these laboratories effectively to accommodate the needs and interests of its current and expanded research staff. The present application requests partial support for a three- component project to improve and develop the Institute's existing animal resources. The specific aims are: 1. Improvement of the Redstone Laboratories' air handling system to enhance the quality of animal health, to assure reliable temperature and humidity environmental controls, and to facilitate mechanical maintenance and repairs without interrupting on-going operations. 2. Development of facilities for conduct of experimental animal research studies with infectious agents requiring biologic containment, including agents infectious for human and rodent hosts and recombinant DNA-derived materials. 3. Improvement and expansion of the Institute's facilities to house and utilize nude mice for experimental studies. Two satellite nude mouse colonies also will be incorporated into the expanded facility to provide uniform care and management.